1. Field of the Invention
The present invention relates to a head assembly that is equipped with a head rotation mechanism such as a micro-actuator in order to achieve high density recording on a magnetic disk drive which is used, for example, as a storage device of a computer.
2. Description of the Related Art
In recent years, high density recording on magnetic disk drives has been advanced. Each magnetic disk drive is provided with a slider that includes a magnetic head for recording and reproducing data on or from the magnetic disk, and the slider is supported by a head support mechanism. The head support mechanism is mounted on a head actuator arm which is rotatably driven by a voice coil motor (VCM). The VCM controls the magnetic head mounted on the slider to be positioned at any point on the magnetic disk. However, in order to achieve further higher density recording on a magnetic disk, it is desirable that accuracy in positioning of the magnetic head on the magnetic disk be further increased. However, accuracy in positioning the magnetic head may not be improved by simply driving the VCM to rotate the head actuator arm and to position the magnetic head.
Japanese Unexamined Patent Application Publication (JP-A) No. 2011-138596 discloses the entire configuration of a head assembly that is equipped with a conventional head rotation mechanism. A flexure at the tip end of the head assembly includes a thin film piezoelectric element, and application of a voltage to the thin film piezoelectric element causes the thin film piezoelectric element to contract, thereby the slider rotates around a support projection and the magnetic head is finely displaced and accurately controlled to be at a position on a track. At this point, head element wiring disposed around the outer perimeter of the thin film piezoelectric element expands and contracts along with a displacement of the thin film piezoelectric element.
A thin film piezoelectric element is formed on a wafer by sputtering, and the number of elements available from a single wafer determines the cost. Thus it is a great challenge to maximize the number of elements that are available from a single process of film formation. Therefore, more efficient drive method is demanded in order to achieve a predetermined displacement with a smaller element.